Merge pull request #517 from ghaerr/cleanup

[mbr] Various standardizations for MBR boot/partitions

elks/arch/i86/defconfig

@@ -94,7 +94,7 @@ CONFIG_FS_DEV=y
 # CONFIG_ROOT_READONLY is not set
 # CONFIG_FS_RO is not set
 CONFIG_FULL_VFS=y
-# CONFIG_32BIT_INODES is not set
+CONFIG_32BIT_INODES=y
 CONFIG_FS_EXTERNAL_BUFFER=y
 CONFIG_PIPE=y
 

elks/arch/i86/drivers/block/genhd.c

@@ -59,24 +59,29 @@ static void print_minor_name(register struct gendisk *hd,
 static void add_partition(struct gendisk *hd, unsigned short int minor,
 			  sector_t start, sector_t size)
 {
-    struct hd_struct *hdp = &hd->part[minor];
-#if 0
     struct hd_struct *hd0 = &hd->part[0];
+    struct hd_struct *hdp = &hd->part[minor];
+
+    hdp->start_sect = start;
+    hdp->nr_sects = size;
+    print_minor_name(hd, minor);
 
-    /* additional partition check since no MBR signature*/
-    if (start > hd0->nr_sects || start+size > hd0->nr_sects) {
-	printk(":skip%d ", minor);
+    /*
+     * Additional partition check since no MBR signature:
+     * Some BIOS subtract a cylinder, making direct comparison incorrect.
+     * A CHS cylinder an have 63 max sectors * 255 heads, so adjust for that.
+     */
+    sector_t adj_nr_sects = hd0->nr_sects + 63 * 255;
+    if (start > adj_nr_sects || start+size > adj_nr_sects) {
+	printk("skipped ");
+	hdp->start_sect = -1;
+	hdp->nr_sects = 0;
 	return;
     }
-#endif
 
     /* save boot partition # based on start offset*/
     if ((int)start == setupw(0x1e4))
 	boot_partition = minor;
-
-    hdp->start_sect = start;
-    hdp->nr_sects = size;
-    print_minor_name(hd, minor);
 }
 
 static int is_extended_partition(register struct partition *p)

elks/fs/super.c

@@ -499,7 +499,10 @@ void mount_root(void)
 	root_mountflags |= MS_RDONLY;
 	retval = open_filp(0, d_inode, &filp);
     }
-    if (retval) panic("VFS: Unable to open root device %s\n", kdevname(ROOT_DEV));
+    if (retval) {
+	printk("VFS: Unable to open root device %s\n", kdevname(ROOT_DEV));
+	halt();
+    }
 
     fs_type = &file_systems[0];
     do {
@@ -535,5 +538,6 @@ void mount_root(void)
     }
 #endif
 
-    panic("VFS: Unable to mount root fs on %s\n", kdevname(ROOT_DEV));
+    printk("VFS: Unable to mount root fs on %s\n", kdevname(ROOT_DEV));
+    halt();
 }

elks/include/linuxmt/kernel.h

@@ -23,6 +23,7 @@ extern int kill_pg(pid_t,sig_t,int);
 
 extern int kill_sl(void);
 
+extern void halt(void);
 extern void panic(char *, ...);
 extern void printk(char *, ...);
 extern void early_printk (char *);

elks/kernel/printk.c

@@ -208,6 +208,15 @@ void printk(char *fmt, ...)
     va_end(p);
 }
 
+void halt(void)
+{
+    /* Lock up with infinite loop */
+    kputs("\nSYSTEM HALTED - Press CTRL-ALT-DEL to reboot:");
+
+    while (1)
+	/* Do nothing */;
+}
+
 void panic(char *error, ...)
 {
     va_list p;
@@ -219,6 +228,7 @@ void panic(char *error, ...)
     va_start(p, error);
     vprintk(error, p);
     va_end(p);
+
     kputs("\napparent call stack:\n"
 	  "Line: Addr    Parameters\n"
 	  "~~~~: ~~~~    ~~~~~~~~~~");
@@ -232,10 +242,5 @@ void panic(char *error, ...)
 	} while ((int)(++j) <= 8);
     } while (++i < 9);
 
-    /* Lock up with infinite loop */
-
-    kputs("\n\nSYSTEM LOCKED - Press CTRL-ALT-DEL to reboot:");
-
-    while (1)
-	/* Do nothing */;
+    halt();
 }

elks/tools/setboot/setboot.c

@@ -64,14 +64,21 @@ static void writePartition(unsigned char *buf)
 
 	/* create partition #1 at sector 2 using max CHS as size*/
 	p->boot_ind = 0x80;
+#if 1
+	p->head = 1;
+	p->sector = 1;				/* next cylinder after MBR, standard*/
+	p->cyl = 0;
+	p->start_sect = NumTracks;	/* zero-relative start sector here*/
+#else
 	p->head = 0;
 	p->sector = 2;				/* next sector after MBR, non-standard*/
 	p->cyl = 0;
+	p->start_sect = 1;			/* zero-relative start sector here*/
+#endif
 	p->sys_ind = 0x80;			/* ELKS, Old Minix*/
 	p->end_head = NumHeads;
 	p->end_sector = SecPerTrk | ((NumTracks >> 2) & 0xc0);
 	p->end_cyl = NumTracks & 0xff;
-	p->start_sect = 1;			/* zero-relative start sector here*/
 	p->start_sect_hi = 0;
 	p->nr_sects = nr_sects & 0xffff;
 	p->nr_sects_hi = nr_sects >> 16;

elkscmd/disk_utils/fdisk.c

@@ -173,8 +173,8 @@ void add_part(void)
 	    return;
     }
 
-#if 0
-    /* skip cylinder 0 head 0 sectors, use head 1 sector 1*/
+#if 1
+    /* skip cylinder 0 head 0 sectors, use head 1 sector 1 (standard)*/
     p.head	= (scyl == 0) ? 1 : 0;
     p.sector	= 1 + ((scyl >> 2) & 0xc0);
 #else
@@ -362,8 +362,8 @@ void list_partition(char *devname)
 	}
     } else
 	memcpy(table,MBR,512);
-    printf("                           START              END           SECTOR\n");
-    printf("Device           #:ID  Head Sect  Cyl   Head Sect  Cyl  Start   Size\n\n");
+    printf("                           START              END          SECTOR\n");
+    printf("Device           #:ID   Cyl Head Sect    Cyl Head Sect  Start   Size\n\n");
     for (i=0; i<4; i++) {
 	struct partition *p = (struct partition *)&table[PARTITION_START + (i<<4)];
 	unsigned long start_sect = p->start_sect | ((unsigned long)p->start_sect_hi << 16);
@@ -376,17 +376,17 @@ void list_partition(char *devname)
 		*p = 0;
 	}
 	//if (p->end_head)
-	    printf("%-15s %c%d:%02x    %2d  %3d%5d     %2d  %3d%5d %6lu  %6lu\n",
+	    printf("%-15s %c%d:%02x    %2d  %3d%5d     %2d  %3d%5d %6lu %6lu\n",
 		device,
 		p->boot_ind==0?' ':(p->boot_ind==0x80?'*':'?'),
 		i+1,			     		     /* #*/
 		p->sys_ind,				     /* Partition type */
+		p->cyl | ((p->sector & 0xc0) << 2),	     /* Start cylinder */
 		p->head,				     /* Start head */
 		p->sector & 0x3f,			     /* Start sector */
-		p->cyl | ((p->sector & 0xc0) << 2),	     /* Start cylinder */
+		p->end_cyl | ((p->end_sector & 0xc0) << 2),  /* End cylinder */
 		p->end_head,				     /* End head */
 		p->end_sector & 0x3f,			     /* End sector */
-		p->end_cyl | ((p->end_sector & 0xc0) << 2),  /* End cylinder */
 		start_sect,				     /* Size*/
 		nr_sects);				     /* Sector count */
     }

image/Makefile

@@ -137,11 +137,11 @@ hd32-fat:
 
 # MBR images
 hd32mbr-minix:
-	dd if=/dev/zero bs=512 count=1 | cat - hd32-minix.bin > hd32mbr-minix.bin
+	dd if=/dev/zero bs=512 count=63 | cat - hd32-minix.bin > hd32mbr-minix.bin
 	setboot hd32mbr-minix.bin -P63,16,63 $(HD_MBR_BOOT)
 
 hd32mbr-fat:
-	dd if=/dev/zero bs=512 count=1 | cat - hd32-fat.bin > hd32mbr-fat.bin
+	dd if=/dev/zero bs=512 count=63 | cat - hd32-fat.bin > hd32mbr-fat.bin
 	setboot hd32mbr-fat.bin -P63,16,63 $(HD_MBR_BOOT)
 
 # Clean target